1. Field of the Invention
This invention relates generally to the field of musical drums, and is more particularly directed to an active, stress relieved tone control device for a drumhead.
2. Description of the Related Art
Modern drumheads are typically constructed of single or multiple layers of synthetic plastic materials such as polyethylene, polypropylene, polyester and the like. A drumhead sheet of plastic material is formed to a shape that will fit over the open end of a drum shell. The peripheral edges of the formed drumhead sheet are secured within a rigid drum hoop, typically constructed of metal. Tensioning devices engage the hoop and adjustably tension the drumhead over the drum shell. Generally speaking, higher tension on the drumhead produces higher pitch vibrations when the drumhead is struck. The “attack” is the initial period of a generated tone. When the drumhead is struck a number of frequencies are excited and the nature of the attack characteristics, the clarity and crispness of the fundamental tones, are developed. Frequency control is a key element to shaping the attack characteristics.
Plastic sheet materials have proven to be exceptionally durable, attractive and adaptable to the manufacture of drumheads for musical drums. Synthetic sheet materials, however, also have some undesirable vibration characteristics that have come to the attention of both musicians and sound engineers. Synthetic drumheads have a tendency toward sustained vibration where the peripheral portions of the drumhead emit unwanted ringing and overtones that detract from the sound of the primary fundamental tones of the drum.
One theory of the cause of ringing is that the vibrations of a plastic drumhead, which result when the drum is struck by the drummer, move radially outwardly toward the edge or rim of the drum, reach the periphery thereof, and are reflected back by the rim. As the reflected vibrations are returning toward the center of the drum, if the drum is struck again, the most recently induced vibrations, which, at this point, are traveling outwardly, will meet the returning reflected vibrations from the previous beat. It is the meeting and crossing of vibrations which causes the effect known as ringing. The crossing vibrations, and resultant sound waves, produce a distorted drum tone which varies in pitch; hence, the term ringing. This phenomenon was not as severe a problem when drumheads were made principally of natural products such as calfskin or other “gut” type materials which do not conduct the reflected vibrations as efficiently as do the synthetic drumhead-membranes.
Since the relatively recent advent of the use of plastic and synthetic drumheads, and the accompanying increase in the ringing phenomenon, drummers have searched for methods of reducing or eliminating this problem, in an effort to achieve a more pure percussive tonal quality. The first, crude efforts of musicians involved placing pillows, rugs, or other materials inside the drum shell and in contact with the drumhead, to reduce the amount of return vibration, thereby reducing the ringing phenomenon. Although moderately effective, the use of such materials in the drum shell is inconvenient, unsightly and impractical for drums which are to be carried by marching band members or the like. Large bulky items, such as pillows or rugs, when stuffed in the drum shell, also retard the originating vibrations to a greater degree than is desirable, hence reducing the volume of the desired percussion. With the popularity of clear plastic drumheads, items such as those mentioned, being stuffed into the drum shell, present a totally unacceptable appearance when used in public performance.
More recently, drum and drumhead manufacturers have taken up the search for effective tone control in synthetic drumheads that is less obtrusive, more effective and adaptable to marching and stationary drums. Currently, the known techniques for dampening a drumhead include adding an additional element that is applied to the drumhead, i.e., a screen printed coating, vinyl or foam applique. An example of such an adhesive patch is seen in U.S. Pat. No. 4,244,266. Screen printed coatings tend to provide inadequate control over drumhead ringing, while vinyl and foam appliques have a tendency toward negative effects on the attack and fundamental tone of the drumhead. Another method currently used is a dampening or tone control device, formed of a polymer film loosely placed against the drumhead about the peripheral edge of the drumhead. The film is not adhered to the drumhead and therefore vibrates out of phase with the drumhead. This technique is shown in U.S. Pat. No. 5,159,139. While devices of this type have been successful, further improvements in tone control are believed possible.
An important objective is to control the amount of overtone content without changing, i.e. dulling, the attack characteristics. This is particularly important because the primary sound that humans relate to in musical listening is attack. In fact, it is considered to be an audio phenomena that the listener is tremendously affected by attack characteristics in tone generated by musical instruments. The attack period of a generated tone communicates the emotion and the rhythmic scheme of a musical performance.